Propeller shaft lock

ABSTRACT

A propeller shaft lock for preventing rotation of windmilling of a boat propeller and controlling its position when its engine is &#39;&#39;&#39;&#39;off&#39;&#39;&#39;&#39; and its transmission is in neutral, comprises a cam mounted on the propeller shaft and having abrupt radial shoulders equal in number to the number of blades comprising the propeller, and a stop member which is movable into and away from the path of rotation of said shoulders. The means for controlling the position of the stop member may be manually controlled mechanical means, or automatic means controlled by the pressure of the oil of the lubricating system of the propeller shaft engine.

United States Patent 1191 Bird 1 1 Aug. 27, 1974 PROPELLER SHAFT LOCK 3,136,399 6/1964 Granryd 188/170 x [76] Inventor: John Lee Bird, Upland Dr.,

Greenwich, Conn. 06830 [22] Filed: Sept. 7, 1972 [21] Appl. No.: 286,675

Related US. Application Data [63] Continuation of Ser. No. 96,053, Dec. 8, 1970,

abandoned.

[52] US. Cl. 115/43, 188/170 [51] Int. Cl B63111 5/06 [58] Field of Search 115/34 R, 43; 188/69, 82.7, 188/170; 416/169; 192/8 R [56] References Cited UNITED STATES PATENTS 278,182 5/1883 Reynolds 115/34 R 985,677 2/1911 Howe 188/69 2,486,672 11/1949 Notestein et al. 188/69 X 2,907,415 10/1959 Norman 188/170 X 2,963,115 12/1960 Peras 188/69 Primary Examiner-Even C. Blunk Assistant Examiner-W. Scott Carson Attorney, Agent, or Firm-Fidelman, Wolffe, Leitner & Hiney ABSTRACT A propeller shaft lock for preventing rotation of wind milling of a boat propeller and controlling its position when its engine is off and its transmission is in neutral, comprises a cam mounted on the propeller shaft and having abrupt radial shoulders equal in number to the number of blades comprising the propeller, and a 4 Claims, 8 Drawing Figures I PROPELLER SHAFT LOCK This is a continuation of application Ser. No. 96,053, filed Dec. 8, 1970, now abandoned.

FIELD OF THE INVENTION This invention relates to means for stopping rotation of a propeller shaft and holding the propeller fixed in predetermined position when its engine is not in operation and its transmission is in neutral. Application of the invention is particularly contemplated in connection with auxiliary engines of sailboats, and also in connection with the propeller shafts of twin engines of a power boat when only one of the engines is being employed to propel the boat.

Propellers used in connection with marine engines usually comprise either two or three blades. When an engine is not operating but the boat is moving, as for example when a sailboat is operating entirely under sail, or, when a twin-engine power boat is employing only one of its engines, the stopped engine propeller shaft transmission is ordinarily in neutral position and the torsional force between the propeller and the water will cause the propeller to rotate or windmill.

The resulting retardation on the speed of the boat is greatest when a pair of propeller blades are disposed horizontally since they then extend into the slip-stream which is along the converging sides of the rear portion of the hull. The drag is least when a pair of blades are disposed vertically for they are then directly behind the rear portion of the hull, which in the case of a sailboat is referred to as the deadwood, and do not extend into the slip-stream. In the case of a three blade propeller the friction is least when one of the blades extends vertically, in which case that one blade is protected by the rear portion of the hull from the slip-stream and the other two blades are disposed at angles of 60 on either side of a vertical line and project only partly into the slip-stream.

Stopping propeller shaft rotation also eliminates the potential danger of extra wear in the marine transmission gears and shaft bearings.

A propeller shaft brake or lock is now a requirement under the rules of the Cruising Club of America and the North American Yacht Racing Union for racing auxiliaries for specific racing contests.

SUMMARY OF THE DISCLOSURE A cam having two or three abrupt radial shoulders, depending upon the number of blades comprising the propeller, is mounted on the propeller shaft for rotation with it. A locking arm is pivotally mounted adjacent to the cam and at one end carries a roller which can serve as a cam follower, and at the other end is connected to means for swinging the pivoted arm to move the roller carrying end into the path of one of the abrupt radial shoulders defined by the cam. When one of the shoulders on the rotating cam strikes the end of the pivoted arm extending into its rotary path further rotary movement of the cam will be stopped immediately except that, if the propeller shaft and the cam thereon are rotating at a high rpm. the roller on the interposed end of the locking arm may function briefly as a cam follower and ride out and over one or more of the shoulders before the rotation of the shaft is completely stopped. The locking arm is able to function briefly as a cam follower because it is mounted so that when it is swung into locking position it is disposed at an angle to a vertical line normal to the radial stop surface and inclined away from the rotational axis of the cam. This position combined with the yielding spring means provided as a part of the pivoted arm control means enables the control arm to swing enough for its roller carrying end to ride over one or more shoulders before completely stopping the rotation of the cam, and thus prevent a too abrupt stopping of the rotation of the propeller shaft.

The position of the pivoted locking arm may be controlled either mechanically, as by a Morse push-pull type cable such as is commercially available equipped with a position holding control knob, or automatically by force provided by a piston moving within a control cylinder and responsive to the pressure within the oil lubricating system of the propeller shaft engine and/or transmission. In the latter case, when the engine is operating the pressure of the oil in its lubricating system will move the piston in the control cylinder against an opposing spring into a position to hold the pivot cam follower arm in the unlocked position. When the engine is turned off the pressure of its lubricating system will fall allowing spring means within the control cylinder to return the piston within its cylinder and cause the pivoted cam follower arm to swing into locking position.

An object of the invention is to provide a positive lock for preventing rotation or windmilling of a boat propeller when its engine is not operating and its transmission is in neutral.

Another object of the invention :is to provide. propeller lock means which may be readily installed for use with existing propeller drive means.

Another object of the invention is to provide means for holding a propeller in fixed predetermined position.

The invention will be best understood if the following description is read in connection with the drawings in which:

FIG. 1 is a side elevation partly cut away of a boat equipped with a manual control embodiment of a propeller shaft lock,

FIG. 2 is a detail view showing the propeller shaft lock mechanism of FIG. 1 in enlarged scale,

FIG. 3 is a cross section taken on the line 3-3 of FIG. 2, showing the spring pressed pivoted arm which cooperates with shoulder means of a cam mounted on the propeller shaft to provide the locking means,

FIG. 4 is a view showing the right hand end of the control cable, part of which is shown in FIG. 3, together with a control knob on the front end of the cable which, when turned, serves either to engage a pin in, or to release it from, a bayonet slot in order to .hold the cable spring under compression with the arm in unlocking position, or to release the spring and allow it to move the arm into locking position,

FIG. 5 is a front elevation of the control knob shown in FIG. 4, indicating its two positions,

FIG. 6 is a front elevation of another embodiment of the invention in which the locking arm is actuated automatically by the pressure of the oil in the lubricating system of the engine which drives the propeller shaft. Oil from the engine system is fed into a cylinder and controls the position therein of a piston which is connected to the locking arm,

FIG. 7 is a cross section taken on the line 7-7 of FIG. 6, and,

FIG. 8 is a side elevation partly in cross section of the locking arm showing its pivotal mounting on a mounting plate at the rear of the engine transmission, and also DESCRIPTION OF THE DISCLOSURE In the embodiment of the invention shown in FIGS. 1-5 a propeller 10 is disposed in a space behind the deadwood 12 of a sailboat and in front of its rudder l4, and is mounted on shaft 16 which at its inner end has the coupling member 18 adapted to be bolted to the coupling member 20 at the opposed end of shaft 22 which extends from the transmission 24 of the engine, by which, when the transmission is engaged, the propeller is driven.

The flanges 18a and 20a of the coupling members 18 and 20 would ordinarily be joined face to face by the bolts b. In carrying out this invention I interpose a cam 26 between the flanges 18a and 20a, boring the cam with bolt holes aligned with those in the flanges 18a and 20a, and secure the cam between the flanges 18a and 20a by extending the bolts b through it. The cam 26 will therefore rotate with the propeller shaft and if the cam is prevented from rotating the propeller shaft will be lockedand cannot rotate.

It will be noted that cam 26 has two abrupt shoulders 28 and that the propeller illustrated in FIG. 1 comprises two blades. If a three-blade propeller is used the cam will be formed with three abrupt shoulders 28.

As best seen in FIG. 3, the locking arm 30 is pivotally mounted for rotation in the plane of the cam on pivot pin 32 projecting from the mounting plate 34 which itself is disposed at the rear end of the transmission 24. A passage 36 is provided extending transversely through the locking arm 30 adjacent its upper end, and through this passage extends one end of a flexible control cable 38, which may be a known cable such as the commercially known Morse push-pull cable. Since the angle between the end of the control cable and the pivoted locking arm will change as the locking arm swings, the passage 36 is made of greater diameter than the diameter of the control cable. In order to insure the required angular freedom and to provide the engagement of the control cable with locking arm 30, the passage 36 is counterbored forming an annular shoulder 37,

- and the end of the control cable passes thru a thin wall bushing 39 disposed between the jam locking nuts 40, which are on. the threaded extremity of the control cable, and the shoulder 37 within passage 36. Bushing 39 allows a pulling force applied to the cable to be transferred to arm 30. Rotation of arm 30 by such pulling force is limited by stop 31.

The lower end of locking arm 30 is bifurcated and between the arms thus provided a roller 42 is rotatably mounted on the cross pin 44. The locking arm 30 is mounted on the mounting plate 34 so that the lower end of the arm can be swung into contact with'the surface of the cam 26 and interposed in the rotary path of the shoulder means 28, and the spring 46 which extends around the outer end of the control cable 38, betweenthe top of the locking arm 30 and a cable clamp 48 also provided on the mounting plate 34, urges arm 30 to swing in a direction to cause the roller 42 at the lower end of the arm to contact the cam surface 26 and to interpose the lower end of the arm in the rotary path of the shoulders 28. If the rpm. of the propeller shaft, turning due to the torsional force of the water against the propeller, is not great, the abutting of the cam shoulder against the lower end of the locking arm will immediately stop the rotation of the cam and the propeller shaft, and, until control cable 38 is pulled to compress spring 46 and swing arm 30 away from locking position, the propeller will be locked and effectively prevented from turning. Cam 26 is mounted in a position such that when one of the shoulders 28 abuts against the lower end of the locking arm and rotation of the propeller shaft is stopped, the propeller 10 will be disposed with its two blades vertical, in which position they are shielded by the deadwood portion of the boat from the slip stream flowing along the sides of the boat. If a three blade propeller is used it will be stopped with one blade disposed in a vertical position.

The pivot 32 for the locking arm 30 is disposed so that, if a boat should be travelling at a speed which causes the propeller shaft to be rotated by the water at a speed such that an abrupt locking action would subject the locking means and the propeller shaft assembly to excess shock the spring 46, which urges the locking arm 30 into cam locking position will yield sufficiently so that, the roller 42 at the lower end of the locking arm 30 can act as a cam follower and can travel out and over at least one interposed shoulder 28, thus extending very briefly the period before the propeller shaft is completely stopped.

As shown in FIGS. 1 and 4 control cable 38 extends into the control station of the boat and has at its upper end the control knob 50 which facilitates pushing or pulling of the cable. When pulled out and rotated it serves to hold the cable in pulled-out unlocking position, and when released its spring means 46 can return it to its pushed-in, locking position. The control cable per se forms no part of this invention but for better explaining its operation the cable is shown in FIG. 4 extending into a sleeve 52 supported by the frame part 54. Within sleeve 52 a bayonet type slot 56 and cooperating pin 58 are provided which when control knob 50 is rotated in one direction, serve to hold the cable pulled forwardly disposing the locking arm in nonlocking position, as when the engine is being used, or when control knob 50 is rotated in the other direction through release the cable 38 and allow spring 46 to swing the locking arm 30 into locking position.

In the embodiment of the invention shown in FIGS. 6 8 the only change from the embodiment shown in FIGS. 1 5 is the actuation of the locking arm 30a. In this embodiment the locking arm is pivotally mounted at its upper end on a mounting plate 34a, as by pivot 60, and its lower end is pivotally connected to the lower end of a piston rod 66 which is axially reciprocal in response to movement of a piston 68 in cylinder 70. Cylinder 70, on the near side of the piston 68 therein, is connected by conduit 72 to the lubricating oil pressure system of the boat engine by which the propeller shaft may be driven. The lower end of locking arm 30a carries pivot 62 which is a cross pin extending between the arms of a clevis member 64 which, at its upper end, is tubular and internaly threaded so that the member can be adjustably connected to piston rod 66.

The cylinder assembly is mounted on a mounting plate 34a which, like plate 34 described above, is located at the rear end of the transmission 24. As shown the cylinder assembly is pivotally mounted on a pivot pin 74 which extends from the mounting plate 34a through the spacing member 76 and through the spherical bearing 78 at the outer end of cylinder cap 80 which extends to the cylinder assembly. The cylinder assembly is thus able to swing sufficiently to compensate for the swinging movement of the lower end of locking arm 30a as it moves toward and away from the locking cam in response to movement of the piston 68 which in turn is responsive to change in pressure within the oil system of the engine. When the engine is running the pressure of the lubricating oil will force the piston 68 outwardly within cylinder 70, thus swinging locking arm 38a into unlocking position. When the engine is stopped and the pressure of its lubricating system falls the piston 68 will be moved inwardly in cylinder 70 by the force of spring 82, thus swinging the lower end of the locking arm into locking position.

There has thus been provided propeller lock means by which the above mentioned objects are accomplished in a simple and dependable way.

What I claim is:

l. A propeller shaft locking device for a boat equipped with an engine having a lubricating oil pressure system driving a power transmission means which comprises a shaft extending from the transmission and having a coupling member at the outer end, a propeller shaft, a propeller having at least two blades at the outer end of said propeller shaft, and a coupling member at its inner end adapted to be interconnected with the coupling member carried by said power shaft, a cam member adapted to rotate with the propeller shaft having at least two equally spaced shoulder means, with the number of shoulder means not exceeding the number of propeller blades, a mounting plate disposed at the rear end of the transmission, a pivot pin projecting rearwardly from the mounting plate, an arm mounted on said pivot pin for rotating in the plane of the cam member, a roller carried at one end of the arm, the arm being of such a length and the pivot pin being so disposed that the arm may be rotated to interpose the rol ler in the path of rotation of the shoulder means de fined by the cam member and to remove the roller from the path of rotation of the shoulder means, and operating means acting on the other end of said arm to yieldingly urge the arm to rotate in a direction to interpose the said roller in the path of rotation of the shoulder means defined by the cam member whereby when said roller abuts against a shoulder means, said propeller will be locked in a predetermined position.

2. The device claimed in claim 1 wherein said operating means includes a flexible control cable, connected to the end of the arm remote from the roller, by which the arm may be rotated to remove the roller from the path of rotation of the shoulder means, said cable extending through and being supported by, means disposed in spaced relation to the connection between the cable and the arm, and spring means between the arm and the cable support means and yieldingly urging the arm to swing in a direction to interpose the roller in the rotary path of the cam shoulder means.

3. The device claimed in claim 1 in which the arm is pivotally mounted on the mounting plate on pivot means disposed at the end of the arm which is remote from the roller thereon, said operating means includes a cylinder having a piston thereon pivotally mounted on the mounting plate for swinging movement, a piston rod extends from the piston beyond the end of the cylinder, and means are provided for pivotally interconnecting the end of the piston rod. to the lower end of said arm, spring means are disposed within the cylinder on one side of a piston tending to move the piston arm in a direction to swing the roller end of the arm to inter pose the roller in the path of rotation of the shoulder means and conduit means are provided communicating between the engine lubricating oil pressure system and the cylinder on the opposite side of the piston from said spring means, whereby when the engine is running the force of the spring is overcome by the pressure of the oil within the lubricating system, and when the engine is stopped and the pressure of the lubricating system falls, the piston will be moved by said spring and will swing the arm to interpose its roller carrying end in the path of rotation of said cam shoulder means.

4. The device claimed in claim 1 wherein said cam member is disposed between said coupling means, means interconnecting the cam member and the coupling members for rotation of the cam member with the coupling members, and the periphery of the cam member extending radially beyond the coupling members. 

1. A propeller shaft locking device for a boat equipped with an engine having a lubricating oil pressure system driving a power transmission means which comprises a shaft extending from the transmission and having a coupling member at the outer end, a propeller shaft, a propeller having at least two blades at the outer end of said propeller shaft, and a coupling member at its inner end adapted to be interconnected with the coupling member carried by said power shaft, a cam member adapted to rotate with the propeller shaft having at least two equally spaced shoulder means, with the number of shoulder means not exceeding the number of propeller blades, a mounting plate disposed at the rear end of the transmission, a pivot pin projecting rearwardly from the mounting plate, an arm mounted on said pivot pin for rotating in the plane of the cam member, a roller carried at one end of the arm, the arm being of such a length and the pivot pin being so disposed that the arm may be rotated to interpose the roller in the path of rotation of the shoulder means defined by the cam member and to remove the roller from the path of rotation of the shoulder means, and operating means acting on the other end of said arm to yieldingly urge the arm to rotate in a direction to interpose the said roller in the path of rotation of the shoulder means defined by the cam member whereby when said roller abuts against a shoulder means, said propeller will be locked in a predetermined position.
 2. The device claimed in claim 1 wherein said operating means includes a flexible control cable, connected to the end of the arm remote from the roller, by which the arm may be rotated to remove the roller from the path of rotation of the shoulder means, said cable extending through and being supported by, means disposed in spaced relation to the connection between the cable and the arm, and spring means between the arm and the cable support means and yieldingly urging the arm to swing in a direction to interpose the roller in the rotary path of the cam shoulder means.
 3. The device claimed in claim 1 in which the arm is pivotally mounted on the mounting plate on pivot means disposed at the end of the arm which is remote from the roller thereon, said operating means includes a cylinder having a piston thereon pivotally mounted on the mounting plate for swinging movement, a piston rod extends from the piston beyond the end of the cylinder, and means are provided for pivotally interconnecting the end of the piston rod to the lower end of said arm, spring means are disposed within the cylinder on one side of a piston tending to move the piston arm in a direction to swing the roller end of the arm to interpose the roller in the path of rotation of the shoulder means and conduit means are provided communicating between the engine lubricating oil pressure system and the cylinder on the opposite side of the piston from said spring means, whereby when the engine is running the force of the spring is overcome by the pressure of the oil within the lubricating system, and when the engine is stopped and the pressure of the lubricating system falls, the piston will be moved by said spring and will swing the arm to interpose its roller carrying end in the path of rotation of said cam shoulder means.
 4. The device claimed in claim 1 wherein said cam member is disposed between said coupling means, means interconnecting the cam member and the coupling members for rotation of the cam member with the coupling members, and the periphery of the cam member extending radially beyond the coupling members. 